Scientists at Moscow State University, together with foreign colleagues, have revealed the secret of the glow of fluorescent organisms. They established a mechanism for the formation of chromophores within fluorescent proteins – groups of atoms that determine the color of a chemical compound. This is reported in an article published in the journal Chemical Science.
Fluorescent proteins are used in biochemistry, molecular biology, and medicine as biomarkers. At the same time, the mechanism of chromophore maturation has not yet been fully understood. In a new study, scientists have inserted a non-canonical photosensitive amino acid into an incompletely formed chromophore of the Venus yellow fluorescent protein. Thus, they fixed the maturation of the chromophore at the intermediate stage of oxidation.
The very structure of the chromophore allows oxygen to gain access to the immature protein molecule through a special molecular channel. Experts have found that the first stage of oxidation involves the formation of an intermediate hydroperoxyl (reactive oxygen species with the addition of a proton) in combination with the separation of a hydrogen atom from the methylene bridge (-CH2-) in the molecule. As a result, a fully conjugated mature chromophore is formed as a result of the release of H2O2 – not only in laboratory conditions, but also inside a living organism.